Field of the Invention
Embodiments of the invention generally relate to release mechanisms for securing and subsequently releasing ball, dart, and/or plug type members from a holding device into a tubular string disposed in a wellbore.
Description of the Related Art
In the drilling of oil and gas wells, a wellbore is formed using a drill bit that is urged downwardly at a lower end of a drill string. After drilling a predetermined depth, the drill string and bit are removed and the wellbore is lined with a string of casing. An annular area is thus formed between the string of casing and the formation. A cementing operation is then conducted in order to fill the annular area with cement. The combination of cement and casing strengthens the wellbore and facilitates the isolation of certain areas of the formation behind the casing for the production of hydrocarbons.
As is well known in the art, during the cementing operation, a pair of cementing plugs may be used to separate the cement slurry from other fluids. A first cement plug (having a rupture disk) may be dropped into the tubular string ahead of the cement slurry, and a second cement plug may be dropped behind the cement slurry. The first cement plug may land at a location near the end of the tubular string, and the pressurized cement slurry behind it may rupture the rupture disk and flow through into the annular area surrounding the tubular string. The second cement plug may force the cement slurry through the tubular string until it lands on the second cement plug, thereby closing fluid flow through and providing a pressure rise indication that the cement slurry has been circulated to the appropriate location. The cementing plugs may then be sheared from the tubular string and/or drilled through for subsequent operations.
The cementing plugs are usually secured in and released from a cementing head that is coupled to the tubular string through which various fluids, including the cement slurry, flow through. Current cementing head designs, however, are inadequate for securing and/or releasing cement plugs quickly and efficiently. Current cementing head designs are also inadequate for effectively allowing fluid flow through the cement head and around the cementing plugs that are disposed in the cementing head.
Therefore, there is a need for new and/or improved holding device release mechanisms for securing and releasing ball, dart, and/or plug type members into a tubular string disposed in a wellbore.